Drillproof cylinder lock



N. B. HURD DRILL PROOF CYLINDER LOCK Filed March 19. 1923 INVENTOR ATTORNEY6.

atented Feb. 2, I92.

NORMAN B. HURD, OF NEW BRITAIN, CONNECTICUT, ASSIGNOR TOTHE AMERICAN HARDWARE CORPORATION, OF

CONNECTICUT.

NEW BRITAIN, CONNECTICUT, A CORPORATIONVOF DRILLYROOF CYLINDER LOCK.

Application filed March 1 9, 1923. Serial No. 626,052.

To all whom it may concern:

Be it known that I, NORMAN B. Hum), a citizen of the United States of America, residing at New Britain, Connecticut, have invented new and useful Improvements in a Drillproof Cylinder Look, of which the following is a specification.

My invention relates to a cylinder lock, and more particularly to a burglar proof or armored lock.

It is an object of the invention to provide an armor face plate for the cylinder and plug of a cylinderlock so as to prevent damage to the pin tumbler elements of the lock by drilling from the front end.

It is a more specific object to provide an armor face plate having novel means for causing the face plate and plug of a cylinder lock to rotate together.

The above objects may be attained by the means disclosed in the drawings illustrating a preferred form of the invention and in which,

Fig. 1 is a View in. side elevation of a lock embodying features of my invention, a portion of the lock being shown in central longitudinal section.

Fig. 2 is a perspective view of the lock shown in Fig. 1, parts being relatively dis placed to illustrate the invention.

5 designates the cylinder of a well known type of cylinder lock. 6 designates a plug rotatably mounted in the cylinder. The cylinder and plug are provided with registering chambers or passages for pin tumbler elements 77.

The front end of the cylinder is rabbeted or cutaway at the periphery so as to form a shoulder seat 8. An armor face plate 9, preferably of hardened steel, is of a size to substantially cover the front of said cylinder and plug. In the form shown, the face plate 9 is rotatably secured to the cylinder by means of a ferrule 10 including the rearwardly extending flange 11 adapted to abut the shoulder seat 8. A plurality of pins such as 12 pass radially through the flange 11 and radially into the cylinder so as to securely hold the ferrule which in turn holds the face plate in place on the cylinder but permits rotation thereof.

The plug 6 has a key slot 13, and the face plate has a corresponding registering key slot 1.; therein. transverse slot .15 is formed in the front face of the plug 6, and

preferably intersects the key slot. The face plate 9 has a depressed portion 16 on the front side forming the boss 17 on the rear side, which boss is adapted to fit within the transverse slot 15 when the parts are assembled. This interfitting slot and boss constitute in effect a tongue and groove connec tion between the plug and face plate which serves to cause the face plate and plug to iotate as a unit under the influence of the ey. It will be seen that with a look as above described, the pin tumbler elements will be protect-ed against damage by drilling from the front end of the cylinder; and, since the ferrule is held in place by means of pins which will normally be covered when the lock is in place, the ferrule cannot be removed so as to remove the armor face plate.

I do not wish to be strictly limited to the form of the invention herein disclosed, since changes may be made within the scope of the appended claims.

I claim:

1. In a cylinder look, a cylinder, a plug rotatably mounted therein, an armor face plate on the front of said cylinder, a ferrule fitting over said armor face plate and secured to said cylinder for securing said face plate to the cylinder but permitting relative rotation thereof on the cylinder, said face plate and said plug having registering key slots therein.

2. In a cylinder look, a cylinder, a plug rotatably mounted therein, an armor face plate for the front end of said cylinder and plug, a ferrule fitting over said face plate and including a rearwardly extending flange extending over saidcylinder, pins extending radially into said cylinder and through the flange on the ferrule for securing the ferrule and face plate to said cylinder, said face plate being free to turn relatively to said cylinder, said cylinder and said plug having registering key slots therein.

3. In a cylinder look, a cylinder, a plug rotatably mounted therein, said plug having a transverse slot across the front face thereof, anarmor face plate rotatably secured to said cylinder, said face plate having a depressed boss thereon fitting in the transverse slotin the front end of said plug, whereby the plug and face plate will be caused to rotate together, said plug and face plate having registering key slots therein.

4:. In a cylinder lock, a cylinder, a plug rotatably mounted therein and having a key a slot, said plug having a transverse slot in the front end thereof intersecting said key slot, an armor face plate for the front end of said cylinder, said face plate having a depressed portion at the front forming a boss on the rear side fitting in the transverse slot in the front of the plug, said face plate having a key slot registering With the key slot in said plug, and a ferrule extending over said face plate and secured to said cylinder.

5. In a cylinder lock, a cylinder having a peripheral rabbet thereon, forming a seat shoulder, a plug rotatably mounted in said plate rotatably vthereon, said plug and face face plate to rotate with said plug, said plug and face plate having registering key slots therein. v

'6. In a cylinder look, a cylinder, a plug rotatably mounted therein, said plug and cylinder having registering passages for pin tumbler elements, anarmor face plate substantially covering the front end of said cylinder and plug, a ferrule fitting over the front end of said cylinder and securing the armor plate 'rotatahly thereon, pins extending radially through said ferrule and radially into said cylinder for securing the ferrule in place thereon, said face plate and said plug having a tongue and groove connection With each other for causing the armor face plate and plug to rotate together, said plug and face plate having registering key slots therein.

NORMAN BHURD.

plate having interlocking tongue and groove connection With each other for causing the 

